Portmanteau shipping name of the slash pairing of Harry Potter characters Dean Thomas and Seamus Finnigan. The ship has fics and fan art of its own, and is often a sub-plot in other Harry Potter fanfiction.

Person one: I ship Deamus
Person two: OMG me too!
Person one: It's just so adorable and I love how they're best friends
Person two: I know, I just love the fact that while Ron and Harry were running round under the invisability cloak they were in the dormitory-
Person one: Do you think it's canon?
Person two: I hope so
Person one: Yeah, I think Dean and Ginny was just a clever ruse
Person two: They totally got together after the war